Loss of formatting is a known problem with pivot charts. There's
information in the following MSKB article, which suggests recording a
macro as you apply the formatting:

Changing a PivotChart removes series formatting in Excel
http://support.microsoft.com/?id=215904


Outlook Convert wrote:
I created a PivotChart and modified the colors for the chart bars. Whenever
I pivot the chart to create different views of the PivotChart, my custom
colors for the chart bars revert back to the default colors. Is there a way
that I can preserve the formatting attributes of my PivotCharts regardless of
how many different views I create? By the way, the same data source is being
used to create different views. Thanks in advanced.


--
Debra Dalgleish
Contextures
http://www.contextures.com/tiptech.html